Semiconductor integrated circuit (IC) technology has experienced rapid progress including the continued minimization of feature sizes and the maximization of packing density. The minimization of feature size relies on improvement in photolithography and its ability to print smaller features or critical dimensions (CD). However, a reticle used in photolithography may experience a chucking or clamping issue that causes the reticle bended and deformed. Ultimately, the unevenness of the reticle will cause overlay error, which is a more serious issue for advanced technology nodes with small features. It is necessary to monitor reticle shape for its flatness but the existing lithography apparatus is not capable of effectively monitoring reticle shape, particularly the major pattern region of the reticle.
Therefore, an apparatus of a lithography patterning and a method utilizing the same are needed to address the above issues.